We investigated the in vivo effect of an aqueous extract (referred to as EF) from Eriobotryae folium on glucokinase and hexokinase activities of diabetes mellitus induced by $interleukin-1{eta};(IL-1{eta})$. After 1 week of $IL-1{eta}$ injection, the levels of serum glucose concentration and insulin secretion were dramatically increased. However, the insulin secretion was decreased with administration of EF. The level of glucose concentration was decreased by EF administration. Furthermore, it was observed that EF was effective in recovering the levels of insulin secretion. Enzyme activities of the glucokinase and hexokinase, which are key enzymes of glucose phosphorylastion, were decreased by $IL-1{eta}$. EF administration to the mice allowed proportional increasing by stimulation of induction of enzyme activities as high as normal group. These results suggested that EF is highly effective in treatment of diabetes mellitus induce by $IL-1{eta}$.